Syntax highlighting for nano (open-policy-agent#3019)

Signed-off-by: Anders Eknert <anders@eknert.com>

docs/content/editor-and-ide-support.md

@@ -16,6 +16,7 @@ evaluation, policy coverage, and more.
 | Atom | [https://github.com/open-policy-agent/opa/tree/master/misc/syntax/atom](https://github.com/open-policy-agent/opa/tree/master/misc/syntax/atom) |
 | Emacs | [https://github.com/psibi/rego-mode](https://github.com/psibi/rego-mode) |
 | IntelliJ IDEA | [https://github.com/vgramer/opa-idea-plugin](https://github.com/vgramer/opa-idea-plugin) |
+| Nano | [https://github.com/scopatz/nanorc](https://github.com/scopatz/nanorc) |
 | Sublime Text | [https://github.com/open-policy-agent/opa/tree/master/misc/syntax/sublime](https://github.com/open-policy-agent/opa/tree/master/misc/syntax/sublime) |
 | TextMate | [https://github.com/open-policy-agent/opa/tree/master/misc/syntax/textmate](https://github.com/open-policy-agent/opa/tree/master/misc/syntax/textmate) |
 | Vim | [https://github.com/tsandall/vim-rego](https://github.com/tsandall/vim-rego) |